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Submission #25709

# Submission time Handle Problem Language Result Execution time Memory
25709 2017-06-23T18:59:18 Z gs14004 Sailing Race (CEOI12_race) C++11
100 / 100
 2556 ms 8096 KB 
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

int adj[505][505],n,k;
int dp[505][505][2];
int dp2[505][505][2];

inline int M(int x){
    if(x > n) return x - n;
    else if(x <= 0) return x + n;
    return x;
}

inline int I(int x){
    return x == n ? 1 : (x+1);
}

inline int D(int x){
    return x == 1 ? n : (x-1);
}

int f(int s, int e, int lview){
    if(~dp[s][e][lview]) return dp[s][e][lview];
    int ret = 0;
    if(lview){
        for (int i=M(e+1); i != s; i = I(i)) {
            if(adj[e][i]){
                int ret1 = f(e,i,0);
                int ret2 = f(s,i,1);
                ret = max(ret,max(ret1,ret2)+1);
            }
        }
    }
    else if(!lview){
        for (int i=M(s+1); i != e; i = I(i)) {
            if(adj[e][i]){
                int ret1 = f(e,i,1);
                int ret2 = f(s,i,0);
                ret = max(ret,max(ret1,ret2)+1);
            }
        }
    }
    return dp[s][e][lview] = ret;
}

int f2(int s, int e, int lview){
    if(s == e) return 0;
    if(~dp2[s][e][lview]) return dp2[s][e][lview];
    int ret = adj[s][e] ? 0 : -1e9;
    if(lview){
        for (int i=M(e+1); i != s; i = I(i)) {
            if(adj[s][i]) ret = max(ret,f2(i,e,1));
        }
    }
    else{
        for (int i=M(s+1); i != e; i = I(i)) {
            if(adj[s][i]) ret = max(ret,f2(i,e,0));
        }
    }
    return dp2[s][e][lview] = ret + 1;
}

int opt[505];
int adj_max1[505][505];
int adj_max2[505][505];

void set_table(int i){
    memset(adj_max1,0,sizeof(adj_max1));
    memset(adj_max2,0,sizeof(adj_max2));
    for (int j=M(i+1); j != i; j = I(j)) {
        for (int k=M(j+2); k != i; k = I(k)) {
            adj_max1[j][k] = max((adj[i][D(k)] ? (1 + f(j,D(k),0)) : 0),adj_max1[j][D(k)]);
        }
    }
    for (int k=M(i-1); k != i; k = D(k)) {
        for (int j=M(k-2); j != i; j = D(j)) {
            adj_max2[j][k] = max((adj[i][I(j)] ? (1 + f(k,I(j),1)) : 0), adj_max2[I(j)][k]);
        }
    }
}

void solve(){
    for (int j=1; j<=n; j++) {
        set_table(j);
        for (int x=M(j+1); x != M(j-2); x = I(x)) {
            for (int i=M(x+2); i != j; i = I(i)) {
                if(!adj[x][i]) continue;
                opt[x] = max(opt[x],1 + f2(i,j,0) + adj_max1[x][i]);
                opt[x] = max(opt[x],1 + f2(i,j,0) + adj_max2[x][i]);
            }
        }
        for (int i=M(j+1); i != M(j-2); i = I(i)) {
            for (int x=M(i+2); x != j; x = I(x)) {
                if(!adj[x][i]) continue;
                opt[x] = max(opt[x],1 + f2(i,j,1) + adj_max1[i][x]);
                opt[x] = max(opt[x],1 + f2(i,j,1) + adj_max2[i][x]);
            }
        }
    }
}

int main(){
    memset(dp,-1,sizeof(dp));
    memset(dp2,-1,sizeof(dp2));
    scanf("%d %d",&n,&k);
    for (int i=1; i<=n; i++) {
        int t;
        while(1){
            scanf("%d",&t);
            if(t == 0) break;
            else adj[i][t] = 1;
        }
    }
    for (int i=1; i<=n; i++) {
        for (int j=1; j<=n; j++) {
            if(!adj[i][j]) continue;
            for (int k=0; k<2; k++) {
                opt[i] = max(opt[i],f(i,j,k) + 1);
            }
        }
    }
    if(k == 1){
        solve();
    }
    int p = (int)(max_element(opt+1,opt+n+1) - opt);
    printf("%d\n%d",opt[p],p);
}

Compilation message

race.cpp: In function 'int main()':
race.cpp:107:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&k);
                         ^
race.cpp:111:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d",&t);
                           ^

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 8096 KB Output is correct
2 Correct 6 ms 8096 KB Output is correct
3 Correct 3 ms 8096 KB Output is correct
4 Correct 6 ms 8096 KB Output is correct
5 Correct 0 ms 8096 KB Output is correct
6 Correct 9 ms 8096 KB Output is correct
7 Correct 3 ms 8096 KB Output is correct
8 Correct 19 ms 8096 KB Output is correct
9 Correct 6 ms 8096 KB Output is correct
10 Correct 6 ms 8096 KB Output is correct
11 Correct 13 ms 8096 KB Output is correct
12 Correct 189 ms 8096 KB Output is correct
13 Correct 466 ms 8096 KB Output is correct
14 Correct 149 ms 8096 KB Output is correct
15 Correct 2186 ms 8096 KB Output is correct
16 Correct 2116 ms 8096 KB Output is correct
17 Correct 1936 ms 8096 KB Output is correct
18 Correct 199 ms 8096 KB Output is correct
19 Correct 2556 ms 8096 KB Output is correct
20 Correct 2429 ms 8096 KB Output is correct